1. Field of the Invention
This invention relates to orthodontic appliances and, more particularly, to elastomeric ligation devices for attachment to brackets on a patient's teeth in order to produce a tractive force urging an arch wire against the brackets.
2. Discussion of the Related Art
Elastomeric O-ring orthodontic ligators are well known and have been used extensively in the field of Orthodontics for over thirty years. Sometimes referred to as A-LASTICS or SPEEDOS, O-ring ligators are usually formed of latex and are adapted to stretch over and secure under the hook shaped projections of individual brackets attached to the teeth of a patient as part of an orthodontic appliance. Each bracket is provided with a lateral slot formed between the oppositely oriented hook shaped projections. The brackets are attached to the patient's teeth in a manner which aligns the slots for receipt of an arch wire therethrough in interjoining relation between the adjacently arranged brackets. The O-ring ligators stretch over and attach under the projecting prongs, crossing over the outer side of the arch wire, to produce a continually acting tractive force which urges the arch wire inwardly against the brackets, and hence the teeth, to assist in correction of tooth positioning.
Early examples of O-ring type ligators are seen in U.S. Pat. No. 3,530,583 to Klein, et al. and U.S. Pat. No. 3,758,947 to Kessling.
For many years, orthodontic appliances were considered to be unattractive and, to some extent, unsightly, causing many orthodontic patients to feel embarrassed by their personal appearance. However, the relatively recent introduction of multi-color O-ring ligators has led to somewhat of a fashion craze, particular among children who are required to wear an orthodontic appliance. The ability to select and wear any particular color ligator, or multiple colors, including vibrant neon colors, is extremely appealing to younger children and teenagers. For instance, orthodontic patients can select ligators of multiple colors to coincide with a particular holiday, such as red, white and blue for Independence day or black and orange for Halloween. Sports fans may choose to wear colors of their favorite team. And, because latex O-ring ligators need to be changed frequently, usually every six to eight weeks, the patient can regularly change the color and/or color pattern to suit their preference. This ability to select and interchange colors has provided an element of fun and fashion to the otherwise mundane experience of wearing an orthodontic device.
Notwithstanding the visual benefits and general appeal of multi-color O-ring ligators in the field of orthodontics, there remains a need to enhance the overall appearance of the orthodontic appliance without altering the structure, performance and overall function of the appliance. More particularly, there remains a need to improve the appearance of orthodontic appliances, while keeping with the fashion trend generated by the introduction of multi-color O-ring ligators, by covering a substantial portion of the brackets, and particularly, the prongs and slots, and displaying an ornamental design, symbol, trademark or other indicia. This would allow the patient to not only wear one or more colors on their appliance, but to also hide the brackets from view and, instead, display an ornamental design (e.g. a star, lightening bolt, flower, etc.) or some other indicia such as sports related symbols (e.g. baseball, football, basketball) or a team or school logo.